[clang-tidy] Generalize TransformerClangTidyCheck to take a rule generator.

Summary: Tidy check behavior often depends on language and/or clang-tidy options. This revision allows a user of TranformerClangTidyCheck to pass rule _generator_ in place of a rule, where the generator takes both the language and clang-tidy options. Additionally, the generator returns an `Optional` to allow for the case where the check is deemed irrelevant/disable based on those options.

Reviewers: gribozavr

Subscribers: xazax.hun, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D63288

llvm-svn: 364442

1 files changed, 59 insertions, 3 deletions

diff --git a/clang-tools-extra/unittests/clang-tidy/TransformerClangTidyCheckTest.cpp b/clang-tools-extra/unittests/clang-tidy/TransformerClangTidyCheckTest.cpp
index 6b8763810e9..6e42be25d5f 100644
--- a/clang-tools-extra/unittests/clang-tidy/TransformerClangTidyCheckTest.cpp
+++ b/clang-tools-extra/unittests/clang-tidy/TransformerClangTidyCheckTest.cpp
@@ -18,16 +18,16 @@ namespace clang {
 namespace tidy {
 namespace utils {
 namespace {
+using tooling::change;
 using tooling::RewriteRule;
+using tooling::text;
+using tooling::stencil::cat;
 
 // Invert the code of an if-statement, while maintaining its semantics.
 RewriteRule invertIf() {
   using namespace ::clang::ast_matchers;
-  using tooling::change;
   using tooling::node;
   using tooling::statement;
-  using tooling::text;
-  using tooling::stencil::cat;
 
   StringRef C = "C", T = "T", E = "E";
   RewriteRule Rule = tooling::makeRule(
@@ -65,6 +65,62 @@ TEST(TransformerClangTidyCheckTest, Basic) {
   )";
   EXPECT_EQ(Expected, test::runCheckOnCode<IfInverterCheck>(Input));
 }
+
+// A trivial rewrite-rule generator that requires Objective-C code.
+Optional<RewriteRule> needsObjC(const LangOptions &LangOpts,
+                                const ClangTidyCheck::OptionsView &Options) {
+  if (!LangOpts.ObjC)
+    return None;
+  return tooling::makeRule(clang::ast_matchers::functionDecl(),
+                           change(cat("void changed() {}")), text("no message"));
+}
+
+class NeedsObjCCheck : public TransformerClangTidyCheck {
+public:
+  NeedsObjCCheck(StringRef Name, ClangTidyContext *Context)
+      : TransformerClangTidyCheck(needsObjC, Name, Context) {}
+};
+
+// Verify that the check only rewrites the code when the input is Objective-C.
+TEST(TransformerClangTidyCheckTest, DisableByLang) {
+  const std::string Input = "void log() {}";
+  EXPECT_EQ(Input,
+            test::runCheckOnCode<NeedsObjCCheck>(Input, nullptr, "input.cc"));
+
+  EXPECT_EQ("void changed() {}",
+            test::runCheckOnCode<NeedsObjCCheck>(Input, nullptr, "input.mm"));
+}
+
+// A trivial rewrite rule generator that checks config options.
+Optional<RewriteRule> noSkip(const LangOptions &LangOpts,
+                             const ClangTidyCheck::OptionsView &Options) {
+  if (Options.get("Skip", "false") == "true")
+    return None;
+  return tooling::makeRule(clang::ast_matchers::functionDecl(),
+                           change(cat("void nothing()")), text("no message"));
+}
+
+class ConfigurableCheck : public TransformerClangTidyCheck {
+public:
+  ConfigurableCheck(StringRef Name, ClangTidyContext *Context)
+      : TransformerClangTidyCheck(noSkip, Name, Context) {}
+};
+
+// Tests operation with config option "Skip" set to true and false.
+TEST(TransformerClangTidyCheckTest, DisableByConfig) {
+  const std::string Input = "void log(int);";
+  const std::string Expected = "void nothing();";
+  ClangTidyOptions Options;
+
+  Options.CheckOptions["test-check-0.Skip"] = "true";
+  EXPECT_EQ(Input, test::runCheckOnCode<ConfigurableCheck>(
+                       Input, nullptr, "input.cc", None, Options));
+
+  Options.CheckOptions["test-check-0.Skip"] = "false";
+  EXPECT_EQ(Expected, test::runCheckOnCode<ConfigurableCheck>(
+                          Input, nullptr, "input.cc", None, Options));
+}
+
 } // namespace
 } // namespace utils
 } // namespace tidy